Like in the topic.
I get that both in desktop and mobile browser (firefox).
I'm pretty sure it wasn't like that before.

printscreen:
cdn.discordapp.com/attach...3147242299440/unknown.png

I'm currently running the latest version of Firefox 73.0.1 (64bit). I've tried the pages at 100, 110, 150, and 300 percent zoom. I have not gotten this kind of web element justification error though. I have gotten the error in the past though, so I know that it is an issue on some devices.
Suggestions: In mobile Firefox, grab and expand to zoom in and that may force an spacing resize (PC FF, use CTRL + Plus sign). ;
make sure that your version of Javascript for Firefox is up-to-date; and if the mobile device is giving this error try the 'request desktop version' from your options.
Try those to see if it'll work.

Also, verify that the latest version is installed from your mobile devices as well as from your PC

Yes it happened for me to, just had to update.